Three‐dimensional contrasted visualization of pancreas in rats using clinical MRI and CT scanners

Abstract

The purpose of this work was to visualize the pancreas in post-mortem rats with local contrast medium infusion by three-dimensional (3D) magnetic resonance imaging (MRI) and computed tomography (CT) using clinical imagers. A total of 16 Sprague Dawley rats of about 300 g were used for the pancreas visualization. Following the baseline imaging, a mixed contrast medium dye called GadoIodo-EB containing optimized concentrations of Gd-DOTA, iomeprol and Evens blue was infused into the distally obstructed common bile duct (CBD) for post-contrast imaging with 3.0 T MRI and 128-slice CT scanners. Images were post-processed with the MeVisLab software package. MRI findings were co-registered with CT scans and validated with histomorphology, with relative contrast ratios quantified. Without contrast enhancement, the pancreas was indiscernible. After infusion of GadoIodo-EB solution, only the pancreatic region became outstandingly visible, as shown by 3D rendering MRI and CT and proven by colored dissection and histological examinations. The measured volume of the pancreas averaged 1.12 ± 0.04 cm(3) after standardization. Relative contrast ratios were 93.28 ± 34.61% and 26.45 ± 5.29% for MRI and CT respectively. We have developed a multifunctional contrast medium dye to help clearly visualize and delineate rat pancreas in situ using clinical MRI and CT scanners. The topographic landmarks thus created with 3D demonstration may help to provide guidelines for the next in vivo pancreatic MRI research in rodents.

Visualization, Quantification and Characterization of Caerulein-Induced Acute Pancreatitis in Rats by 3.0T Clinical MRI, Biochemistry and Histomorphology

“…To summarize, in addition to previously introduced 3D MRI visualization of normal pancreas 12 and pancreatic head tumor 35, here, we described the rat model of Caerulein-induced acute pancreatitis as well as the in vivo and ex vivo experiments by using multiparametric MRI for qualitative and quantitative assessment of this model as a potential platform for further translational theranostic research.…”

“…Until now, due to a lack of specific markers, imaging the pancreas as an irregular lobulated organ in rodents remains extremely challenging. In previous studies, volumetric MR measurements were performed in post-mortem rodent models to reveal the anatomical relationship of rodent pancreas against adjacent organs 11, 12. However, in vivo imaging studies directly on rodent pancreas have been greatly hampered by the tiny size of pancreas and random motion artifact within abdomen.…”

“…Caerulein induced AP in rats is a well-established model in preclinical research, which shows similar structural changes characterized by edema, acinar cell loss and inflammatory cell infiltration, comparable to human AP 16-18. Although Caerulein induced AP has been used for decades in rodent pancreatitis studies and therapeutic investigations, none of those studies involved pancreatic imaging due to the difficulties in visualizing this organ of rodent species by both in vivo imaging and ex vivo dissection 12. Therefore, in this preclinical study, we sought to explore noninvasive MR imaging methods to investigate the Caerulein induced AP in rats, which may pave the path for further translational research using rodent models of pancreatitis.…”

Characterization of a rat orthotopic pancreatic head tumor model using three‐dimensional and quantitative multi‐parametric MRI

“…The recipient animal was anesthetized with 40 mg/kg of pentobarbital by intraperitoneal administration, and a mid‐line abdominal incision was made to expose the pancreas. A small cube (approximately 1 mm 3 ) of R1 tumor was transplanted into the pancreatic head next to the common bile duct (CBD), guided anatomically by earlier studies, and sealed with tissue glue (Histoacryl; Aesculap, Tuttlingen, Germany). Recipient animals were maintained in the animal facility for follow‐up studies.…”

“…Animals were euthanatized using an intravenous overdose of pentobarbital (Nembutal; Sanofi Sante Animale, Brussels, Belgium) immediately after the last MRI scan. Rat pancreas was locally infused with 10% Evans blue dye (Sigma‐Aldrich, Saint Louis, MO, USA) through CBD, as demonstrated by a video recording (Supplement 3). Guided as such, the tumor together with surrounding pancreatic tissue was entirely dissected, fixed in 4% PBS‐buffered formalin, paraffin embedded, sectioned into 5 μm slices, stained with hematoxylin‐eosin, assessed under a light microscope (Axioskop; Zeiss, Oberkochen, Germany), and digitally photographed.…”